The invention relates to feeler or tracer apparatus for the testing of gear forms and is concerned with the provision of means for lifting a probe or feeler from a gear tooth flank under measurement and/or changing over the setting of the probe or feeler for respective measurements on left-hand and right-hand tooth flanks.
In a known gear testing apparatus, the probe or feeler can be lifted from a tooth flank by means of an electromagnet which is continuously on after the lifting operation and during the measurement process. Due to the long period for which the electromagnet is switched on, a heating effect occurs which has an effect on the measurement. In addition, with this known apparatus a change-over from the pitch measurement of left-hand tooth flanks to that of right-hand tooth flanks has to be effected manually by another arrangement of the separate feelers.
One object of the invention is to limit a minimum the heating of the apparatus by the mechanism for said adjustments of the probe or feeler in order to avoid any influence on the results of measurements. Another object of the invention is to eliminate the necessity for manual adjustment when changing over from the measurement of one tooth flank to an oppositely facing flank.